Bi Qi
StarEleocharis dulcis (Burm.f.) Trin. ex Hensch.
Traditionally used for
- Eye health
- Nose & throat
- Cough & breathing
- Colds & fever
- Digestion
- Bowel health
- Urinary & fluids
- Liver & jaundice
☯ TCM Properties
Transforms Phlegm and reduces accumulations; Clears Lung and Stomach Heat, generates Fluids and stops thirst; Cools the Blood, removes toxins, promotes bowel movement and improves the appetite
Traditional Chinese Uses
Bi Qi (Rhizoma/Cormus Eleocharitis) is the corm of the Chinese water chestnut, Eleocharis dulcis, a substance that transforms Phlegm and clears Heat. Sweet and cold, entering the Lung, Stomach and Large Intestine channels, it clears Lung and Stomach Heat, transforms Phlegm and reduces accumulations, and is used for cough with thick sputum from Phlegm-Heat, and for sore, swollen throat and red, painful eyes.
Being cold and juicy, it generates Fluids and relieves thirst, making it useful for Heat patterns with dry mouth, wasting-and-thirsting (xiao ke) presentations and febrile-disease fluid damage; it also cools the Blood, resolves toxicity, moistens the intestines to promote bowel movement and settles the appetite, and is applied to jaundice and heat-type painful urination. It is eaten fresh, juiced or lightly decocted (its actives are heat-sensitive). It is contraindicated in Spleen-Stomach deficiency-Cold with loose stools.
Western Herbalism Properties
Relationships
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Botanical Description
Eleocharis dulcis (Burm.f.) Trin. ex Hensch. (Cyperaceae), the Chinese water chestnut or ma-tai, is an aquatic perennial sedge cultivated throughout southern China and Southeast Asia. It produces tufted, leafless cylindrical green culms 50-100 cm tall arising from creeping rhizomes that terminate in flattened, dark-brown, scaly corms 2-4 cm in diameter. The reduced inflorescence is a small terminal spikelet bearing tightly imbricated glumes. The edible corm has a crisp white interior and sweet flavour, eaten fresh or used in cooking. In TCM it is used to clear heat, transform phlegm, moisten dryness, and disperse accumulations. Cultivation occurs in shallow flooded paddies; the species is native to tropical Asia, Africa, and northern Australia.
Active Constituents
Starch
Polysaccharide (storage carbohydrate)Concentration: Major component of the corm dry matter
The predominant storage carbohydrate of the water chestnut corm, giving it its characteristic crisp, starchy flesh. It is the principal source of the herb's fluid-generating and nourishing qualities and forms the bulk of the edible tuber.
Puchiin
Antimicrobial phenolic constituentConcentration: Trace (thermostable)
A heat-stable antibacterial agent isolated from the corm that remains active after high-temperature exposure. It has been associated with inhibitory activity against several bacteria and is often cited as the basis for the corm's traditional use against Heat and toxin.
Ferulic acid and feruloyl oligomers
Hydroxycinnamic acid / phenylpropanoidConcentration: Present in cell walls and peel
Phenolic acids that cross-link and strengthen the corm cell walls (contributing to the flesh remaining firm after cooking). They contribute antioxidant and free-radical-scavenging activity attributed to the peel and sarcocarp.
Tricin
FlavoneConcentration: Notable flavonoid of the peel
One of the most abundant flavones identified by metabolomic profiling of chufa peel, present with several hexoside and malonylhexoside derivatives. Associated with antioxidant and antiproliferative activity in laboratory studies.
Luteolin
FlavoneConcentration: Minor flavonoid
A flavone detected in the corm and peel that contributes to the antioxidant and anti-inflammatory profile of the extract.
p-Coumaric acid
Hydroxycinnamic acid / phenolic acidConcentration: Minor phenolic
A phenolic acid identified among the phenylpropanoid metabolites of the peel, contributing to overall antioxidant capacity.
Quercetin
FlavonolConcentration: Minor flavonoid
A flavonol contributing to radical-scavenging activity; part of the broad flavonoid fraction concentrated in ethanol extracts of the corm.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 60–120 g | Daily | — | — | Standard oral dose per Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, pp. 278–279. Exact wording: Normally, 60–120 g is decocted with water or pounded to extract the juice as an oral |
Preparation Methods
Decoction
Parts: corm (fresh or dried tuber/rhizome)
Dried or fresh corms are sliced and simmered in water, alone or with other Heat-clearing, Phlegm-transforming herbs. Typical dosages of the fresh corm are large (dozens of grams to several corms). The decoction is used to clear Lung and Stomach Heat and generate fluids.
Fresh juice (expressed)
Parts: peeled fresh corm
Peeled fresh corms are crushed and the juice expressed and taken directly, sometimes combined with pear, lotus root or reed juice. This preparation is favored to generate fluids, quench thirst and cool Blood in febrile conditions.
Eaten fresh or cooked as food
Parts: peeled corm
The peeled corm is eaten raw as a crisp fruit or cooked in dishes; used dietetically to moisten dryness, promote bowel movement and improve appetite. The peel should be removed and the corm washed thoroughly because of possible waterborne contaminants.
Dui Yao — Herb Pairs
The classical two-herb combinations this herb appears in, each with an action neither herb has alone.
Clears heat and transforms phlegm while moistening dryness and the intestines, for phlegm-heat with constipation.
A food-based formula favored by later warm-disease physicians.
Core pair of a classical formula — Xue Geng Tang, Jiang Xue Yuan Gu Fang Xuan Zhu (Wang Jinsan)
Evidence Tier
Limited evidence · 2 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
0
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
1
0 verified · 1 unverified
Other / unclassified
1
0 verified · 1 unverified
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Antidiabetic and anticancer activity of Chinese water chestnut (Eleocharis dulcis) extract with multistage extraction
Multistage (n-hexane, ethyl acetate, ethanol) extracts of water chestnut were assayed for alpha-glucosidase inhibition and cytotoxicity. The ethanol extract, richest in phenolics and flavonoids, showed the strongest antidiabetic activity (65.74% alpha-glucosidase inhibition at 2000 ppm), while the ethyl acetate extract was most cytotoxic (IC50 ~941 ppm).
Identification of compounds from chufa (Eleocharis dulcis) peels by widely targeted metabolomics
Widely targeted UPLC-MS/MS metabolomics identified 321 metabolites in chufa peel, including 87 flavonoids (tricin, chrysoeriol, luteolin, apigenin, quercetin, kaempferol) and 25 phenylpropanoids (feruloyl-hydroxycoumarins, caffeic aldehyde, p-coumaric and vanillic acids), documenting the phenolic basis of the peel's bioactivity.
⚠ Safety & Contraindications
Contraindications
Its use is cautious in patients with deficiency-cold or blood deficiency.
Source: Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, pp. 278–279.
Historical Texts
Ben Cao Gang Mu (Compendium of Materia Medica), Li Shizhen
Ming dynasty, 1596Ri Yong Ben Cao (Materia Medica for Daily Use)
Yuan dynasty, 14th centuryReferences
- Zhang Y, Zhu H, et al.. Water chestnut (Eleocharis dulcis) corm: phytochemicals, health benefits, processing and food products . Journal of the Science of Food and Agriculture (2022) [DOI]
- Baehaki A, Widiastuti I, Lestari S, Masruro M, Putra HA. Antidiabetic and anticancer activity of Chinese water chestnut (Eleocharis dulcis) extract with multistage extraction . Journal of Advanced Pharmaceutical Technology & Research (2021) [DOI]
- Li G, Huang S, Li X, Luo Y, Nie H. Identification of compounds from chufa (Eleocharis dulcis) peels by widely targeted metabolomics . Food Science & Nutrition (2022) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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